Palliated Hypoplastic Left Heart Syndrome Patients Experience Superior Waitlist and Comparable Post-Heart Transplant Survival to Non-Single Ventricle Congenital Heart Disease Patients

Abstract

Congenital heart disease (CHD) is a well-established risk factor for inferior waitlist and post-heart transplant survival in children. Differences in outcomes between CHD subgroups are understudied. The present study compared outcomes for palliated hypoplastic left heart syndrome (HLHS) patients to other non-single ventricle CHD (non-SVCHD) and non-CHD patients. United Network for Organ Sharing was used to identify children (age < 18) listed for heart transplant in the United States between 2016 and 2021. CHD sub-diagnoses were only available for United Network for Organ Sharing status 1a after 2015, thereby defining the cohort. Waitlist outcomes were studied using competing-risk time-to-event analysis for transplantation, mortality/decompensation, and alive-on-waitlist. Multivariable Cox proportional hazards regression analyses were used to identify factors associated with inferior post-transplant survival. Patients included: palliated-HLHS (n = 477), non-SVCHD (n = 686), and non-CHD (n = 1261). At listing, Palliated-HLHS patients were older than non-SVCHD (median 2-year [IQR 0-8] vs median 0-year [0-3], respectively) and younger than non-CHD (median 7-year [0-14]) (P < 0.001 vs both), and were more likely to be white (P < 0.01 vs both). Upon time-to-event analysis, rates of waitlist mortality/decompensation rates were greater among non-SVCHD than palliated-HLHS. Post-transplant survival was comparable between palliated-HLHS and non-SVCHD (P = 0.920) but worse compared to non-CHD (P < 0.001). Both palliated-HLHS (HR 2.40 [95% CI 1.68-3.42]) and non-SVSCHD (2.04 [1.39-2.99]) were independently associated with post-transplant mortality. Palliated-HLHS patients with heart failure experience significantly worse post-transplant outcomes than non-CHD but, compared to other CHD patients, experience superior waitlist and comparable post-transplant survival. While a high-risk cohort, HLHS patients can achieve gratifying waitlist and post-transplant survival.

Keywords: Clinical outcomes; Congenital cardiac surgery; Congenital heart disease; Heart transplantation; Hypoplastic left heart syndrome; Norwood procedure; Quality improvement.